Poor wording on my part -- sorry about that.
Pressing the ctrl+k in PM opens a window listing the key words available to add to a photo. Maybe there is a shortcut that I have not found but currently I click once on the key word then move the cursor down the screen and click on Apply to Selected Photos. If instead the user could just double click on the key word to add it to the metadata of the selected photos that might shorten the time to imbed the key word.
I suspect that feature is available and I just don't know where to find it.
Double clicking to select and then act on the selection is common in most of the software I use in Windows 10. It's certainly not an exclusive feature to Windows-- just one that is used almost generically in lots of software programs.
Thanks for listening ... marcopolo